The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

featherbristle beaksedge

brown beaksedge, rhynchospore brun

Habit Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent. Plants perennial, cespitose, 10–50 cm; rhizomes stoloniferous, slender.
Culms

filiform, leafy at base, wiry.

erect to excurved, filiform, leafy, ± terete.

Leaves

ascending to erect;

blades filiform, nearly terete, or channeled, sometimes compressed, nearly reaching distal inflorescence or much shorter, 0.2–0.3 mm thick, apex subulate.

shorter than culm;

blades ascending, filiform, proximally to 1.5(–2)mm wide, apex trigonous, tapering, setaceous.

Inflorescences

spikelet clusters 2–6, simple or reduced to 1 spikelet, branches ascending to divaricate or reflexed; leafy bracts single per cluster, filiform, setaceous, with clusters appearing lateral to bracts.

lateral spikelet clusters (0–)1–2, distant, terminal cluster ellipsoid to broadly turbinate or hemispheric, branches ascending; leafy bracts setaceous, overtopping clusters.

Spikelets

pale redbrown, ellipsoidlanceoloid, 5–6(–8) mm, apex acute to acuminate;

fertile scales oblongelliptic, convex, acuminate, 3.5–5 mm, apex broadly acute, midrib forming apiculus.

red-brown to deep brown, lanceoloid, (4–)5–6(–7) mm, apex acute;

fertile scales lanceolate, 4–5(–6) mm, apex acuminate, midrib often excurrent as awn.

Flowers

perianth bristles 6, reaching to or slightly past tubercle base, increasingly plumose from middle to base.

bristles 5–6, longest reaching at least past tubercle base, mostly to tip or beyond, antrorsely barbellate.

Fruits

1–3 per spikelet, (2.5–)2.7–3(–3.4) mm;

body light brown to brown, ellipsoidobovoid, distally conspicuously necked, tumidly lenticular, 1.7–2.5 × 1.5–1.8 mm;

surfaces smooth or minutely transversely rugulose;

tubercle conicsubulate, 0.5–0.7 mm, base flaring.

2(–3) per spikelet, (2.3–)2.5–2.6(–3) mm with pedicellar joint, receptacle, and tubercle;

body lustrous, pale brown to deep brown, obovoid to ellipsoid, lenticular, 1–1.5 × 1 mm, margins narrow, flowing to tubercle;

surfaces longitudinally finely lined, transversely very finely ridged with wavy rows of very narrow, vertical lattices, sometimes also with lines of shallow pits;

tubercle triangularsubulate, (0.7–)1–1.3(–1.5) mm, base lunate, margins setulose proximally.

Rhynchospora oligantha

Rhynchospora fusca

Phenology Fruiting spring–summer. Fruiting summer–fall.
Habitat Sands and peats of bogs, depressions in savannas, open pinelands, seeps Sands and peats of pond shores, bogs, and seeps
Elevation 0–200 m (0–700 ft) 0–400 m (0–1300 ft)
Distribution
from FNA
AL; DC; DE; FL; GA; LA; MS; NC; NJ; SC; TX; VA; Central America; West Indies
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DE; IL; IN; MA; MD; ME; MI; MN; NH; NJ; NY; PA; RI; VT; WI; NB; NL; NS; ON; QC; SK; Europe
[WildflowerSearch map]
[BONAP county map]
Discussion

Rhynchospora oligantha is distinguished from other taxa of its complex mostly by the distinctive neck at the achene apex, a feature essentially absent in R. breviseta, its closest relative. Those two species have been heavily impacted by conversion of pine savannas to cropland or pine plantations; even with abandonment or clearing of such land, they are very slow to reoccupy the disturbed sites.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 23, p. 218. FNA vol. 23, p. 232.
Parent taxa Cyperaceae > Rhynchospora Cyperaceae > Rhynchospora
Sibling taxa
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. oligantha, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
Synonyms Schoenus fuscus, Phaeocephalum fuscum, R. alba var. fusca
Name authority A. Gray: Ann. Lyceum Nat. Hist. New York 3: 212. (1835) (Linnaeus) W. T. Aiton: in W. Aiton and W. T. Aiton, Hortus Kew. 1: 127. (1810)
Web links